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Hydro Booster Pump fault after ABS unit replacement

Discussion in 'Newbie Forum' started by Mae Reed, Jan 10, 2022.

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  1. Mae Reed

    Mae Reed New Member

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    Hello Prius knowledge havers,
    I've recently had the ABS unit in my car replaced but it still showed error codes. After not driving it for a while the errors have gone away on their own! Does that mean the problem's gone away? I've provided details of the nature of the problem below. Thanks in advance for any advice you provide :)

    September 2021 - ABS, (!) warning lights stay on for first 5 mins of driving then turn off.

    One week later - took to local motor mechanic for a general service and diagnosis. They offered to search for 2nd hand part for replacement.

    October 2021 - ABS, (!) lights stay on entire drive and a persistent horrible beep begins sounding 5 min into drive and stays on for the entire drive.

    November 2021 - ABS unit replaced with salvaged second hand module, ABS and (!) light stay on for first 30 seconds of drive then flick off. Problem solved?
    • 3 drives later the horrible beep comes back on.
    • Take it back to the mechanic who runs error codes and finds c1253 HYDRO BOOSTER PUMP RELAY MOTOR fault and offer to replace the relay which I declined to do my own research.
    • My house mate who is an ex-mechanic checks the relays and confirms they all work fine.
    December 2021 - Toyota specialist who ran diagnostics, found the replacement ABS was still faulty, received the following codes:

    C1252 HYDRO BOOSTER PUMP

    C1253 HYDRO BOOSTER PUMP RELAY MOTOR

    C1313 OPEN CIRCUIT IN THE MAIN RELAY 2
    • Found the problem to be 3 wires in the break actuator module not having any resistance when they should, quoted $6128 for supply and fit of new unit.
    • Called the other mechanic and explained the ABS unit they replaced was faulty, they offered to redo the fix with another salvaged ABS unit as it is still within the 3 month warranty for second hand parts.
    • Their supplier sent the wrong part but said they were getting another one in the following week during their xmas break. They would replace it in the new year.
    January 2022 - after weeks of not driving, I turn it on again and error lights immediately turn off and no more beep. Wth?

    I tested the abs by slamming the breaks on a couple times, the car shuddered to a halt once and another time also made a slight screeching sound. The breaks were never dull this whole time either.

    The economy is also not the best sitting at 5.3L/100 km where it should be at about 4.4L/100km

    What do I do?
    Is the car safe to drive??
    Should I still pursue the replacement ABS?

    Thanks for reading all that!
     

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    #1 Mae Reed, Jan 10, 2022
  2. bisco

    bisco cookie crumbler

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    have you checked all the brake pads and discs?
     
    #2 bisco, Jan 10, 2022
  3. ChapmanF

    ChapmanF Senior Member

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    Do you have access to a way of reading the brake trouble codes yourself in case any of the lights or the alarm tone coming back?

    I can't overstate how important it is to know the trouble codes, not just which lights are on. A gold standard would be an old laptop computer with Toyota Techstream loaded on it, but at the very least I suggest getting acquainted with the way to read brake system trouble codes with a jumper wire, counting light blinks.

    Finally, the advice that is usually hardest to follow: if the symptoms return, the only sure-fire path to a solution is to methodically gather evidence about where the issue lies. That is much easier with access to the repair manual (more info), and it just plain takes time and effort to do. Often people want there to be a direct path to an answer from the symptoms and trouble codes alone.

    For example, suppose there is a code whose terse "fortune cookie" comes up as something to do with the booster pump or its relays. You have to remember that the computer is giving that code based on partial information. The computer may actually only know that it tried to run the pump and the pump didn't run. Is that because the pump is bad, or the relay is bad? The code may suggest those as likely causes, but they're not the only possibilities, right? There could be a wiring or connection issue, for example. The car's computer, trapped in a box under the dash with no eyes or opposable thumbs to investigate with, can only give codes that are useful for humans as starting points for investigating further.

    Some of the most frustrating situations can result from not checking all the possibilities up front, perhaps overlooking a simple wiring issue, say, and instead replacing a series of expensive parts, only to eventually find the simpler issue that was the cause the whole time.

    That's the kind of frustration one hopes to avoid with more thorough diagnostic efforts at the outset.
     
    #3 ChapmanF, Jan 10, 2022
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